// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/threading/watchdog.h"

#include "base/logging.h"
#include "base/macros.h"
#include "base/synchronization/spin_wait.h"
#include "base/threading/platform_thread.h"
#include "base/time/time.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace base {

namespace {

    //------------------------------------------------------------------------------
    // Provide a derived class to facilitate testing.

    class WatchdogCounter : public Watchdog {
    public:
        WatchdogCounter(const TimeDelta& duration,
            const std::string& thread_watched_name,
            bool enabled)
            : Watchdog(duration, thread_watched_name, enabled)
            , alarm_counter_(0)
        {
        }

        ~WatchdogCounter() override { }

        void Alarm() override
        {
            alarm_counter_++;
            Watchdog::Alarm();
        }

        int alarm_counter() { return alarm_counter_; }

    private:
        int alarm_counter_;

        DISALLOW_COPY_AND_ASSIGN(WatchdogCounter);
    };

    class WatchdogTest : public testing::Test {
    public:
        void SetUp() override { Watchdog::ResetStaticData(); }
    };

} // namespace

//------------------------------------------------------------------------------
// Actual tests

// Minimal constructor/destructor test.
TEST_F(WatchdogTest, StartupShutdownTest)
{
    Watchdog watchdog1(TimeDelta::FromMilliseconds(300), "Disabled", false);
    Watchdog watchdog2(TimeDelta::FromMilliseconds(300), "Enabled", true);
}

// Test ability to call Arm and Disarm repeatedly.
TEST_F(WatchdogTest, ArmDisarmTest)
{
    Watchdog watchdog1(TimeDelta::FromMilliseconds(300), "Disabled", false);
    watchdog1.Arm();
    watchdog1.Disarm();
    watchdog1.Arm();
    watchdog1.Disarm();

    Watchdog watchdog2(TimeDelta::FromMilliseconds(300), "Enabled", true);
    watchdog2.Arm();
    watchdog2.Disarm();
    watchdog2.Arm();
    watchdog2.Disarm();
}

// Make sure a basic alarm fires when the time has expired.
TEST_F(WatchdogTest, AlarmTest)
{
    WatchdogCounter watchdog(TimeDelta::FromMilliseconds(10), "Enabled", true);
    watchdog.Arm();
    SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(TimeDelta::FromMinutes(5),
        watchdog.alarm_counter() > 0);
    EXPECT_EQ(1, watchdog.alarm_counter());
}

// Make sure a basic alarm fires when the time has expired.
TEST_F(WatchdogTest, AlarmPriorTimeTest)
{
    WatchdogCounter watchdog(TimeDelta(), "Enabled2", true);
    // Set a time in the past.
    watchdog.ArmSomeTimeDeltaAgo(TimeDelta::FromSeconds(2));
    // It should instantly go off, but certainly in less than 5 minutes.
    SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(TimeDelta::FromMinutes(5),
        watchdog.alarm_counter() > 0);

    EXPECT_EQ(1, watchdog.alarm_counter());
}

// Make sure a disable alarm does nothing, even if we arm it.
TEST_F(WatchdogTest, ConstructorDisabledTest)
{
    WatchdogCounter watchdog(TimeDelta::FromMilliseconds(10), "Disabled", false);
    watchdog.Arm();
    // Alarm should not fire, as it was disabled.
    PlatformThread::Sleep(TimeDelta::FromMilliseconds(500));
    EXPECT_EQ(0, watchdog.alarm_counter());
}

// Make sure Disarming will prevent firing, even after Arming.
TEST_F(WatchdogTest, DisarmTest)
{
    WatchdogCounter watchdog(TimeDelta::FromSeconds(1), "Enabled3", true);

    TimeTicks start = TimeTicks::Now();
    watchdog.Arm();
    // Sleep a bit, but not past the alarm point.
    PlatformThread::Sleep(TimeDelta::FromMilliseconds(100));
    watchdog.Disarm();
    TimeTicks end = TimeTicks::Now();

    if (end - start > TimeDelta::FromMilliseconds(500)) {
        LOG(WARNING) << "100ms sleep took over 500ms, making the results of this "
                     << "timing-sensitive test suspicious.  Aborting now.";
        return;
    }

    // Alarm should not have fired before it was disarmed.
    EXPECT_EQ(0, watchdog.alarm_counter());

    // Sleep past the point where it would have fired if it wasn't disarmed,
    // and verify that it didn't fire.
    PlatformThread::Sleep(TimeDelta::FromSeconds(1));
    EXPECT_EQ(0, watchdog.alarm_counter());

    // ...but even after disarming, we can still use the alarm...
    // Set a time greater than the timeout into the past.
    watchdog.ArmSomeTimeDeltaAgo(TimeDelta::FromSeconds(10));
    // It should almost instantly go off, but certainly in less than 5 minutes.
    SPIN_FOR_TIMEDELTA_OR_UNTIL_TRUE(TimeDelta::FromMinutes(5),
        watchdog.alarm_counter() > 0);

    EXPECT_EQ(1, watchdog.alarm_counter());
}

} // namespace base
